A step toward clothing that guards against chemical warfare agents

September 30, 2015

Recent reports of chemical weapons attacks in the Middle East underscore the urgent need for new ways to guard against their toxic effects. Toward that end, scientists report in the journal ACS Applied Materials & Interfaces a new hydrogel coating that neutralizes both mustard gas and nerve agent VX. It could someday be applied to materials such as clothing and paint.

Toxic chemicals have been used as weapons since ancient times, but it wasn't until World War I that they were released in large-scale attacks. Despite international efforts to ban them, chemical warfare agents (CWA) are still deployed. Scientists have developed some substances that can neutralize CWAs, but they lose their effectiveness when incorporated into practical coatings such as paint. Lev Bromberg, a research scientist in T. Alan Hatton's group, and other colleagues wanted to come up with a better solution.

The researchers developed hydrogel materials that completely broke down the nerve gas VX—one of the most dangerous and persistent CWAs—in less than 20 minutes. The materials also quickly degraded mustard gas and soman, a nerve agent that was reportedly used in the 1980s during the Iran-Iraq war. And, the researchers say, the hydrogels could be applied to fabrics or other materials without losing their ability to neutralize CWAs.

AbstractWater- and solvent-soluble polymeric materials based on polyalkylamines modified with nucleophilic groups are introduced as catalysts of chemical warfare agent (CWA) hydrolysis. A comparative study conducted at constant pH and based on the criteria of the synthetic route simplicity, aqueous solubility, and rate of hydrolysis of CWA mimic, diisopropylfluorophosphate (DFP), indicated that 4-aminopyridine-substituted polyallylamine (PAAm-APy) and polyvinylamine substituted with 4-aminopyridine (PVAm-APy) were advantageous over 4-pyridinealdoxime-modified PVAm and PAAm, poly(butadiene-co-pyrrolidinopyridine), and PAAm modified with bipyridine and its complex with Cu(II). The synthesis of PVAm-APy and PAAm-APy involved generation of a betaine derivative of acrylamide and its covalent attachment onto the polyalkylamine chain followed by basic hydrolysis. Hydrogel particles of PAAm-APy and PVAm-APy cross-linked by epichlorohydrin exhibited pH-dependent swelling and ionization patterns that affected the rate constants of DFP nucleophilic hydrolysis. Deprotonation of the aminopyridine and amine groups increased the rates of the nucleophilic hydrolysis. The second-order rate of nucleophilic hydrolysis was 5.5- to 10-fold higher with the nucleophile-modified gels compared to those obtained by cross-linking of unmodified PAAm, throughout the pH range. Testing of VX and soman (GD) was conducted in 2.5–3.7 wt % PVAm-APy suspensions or gels swollen in water or DMSO/water mixtures. The half-lives of GD in aqueous PVAm-APy were 12 and 770 min at pH 8.5 and 5, respectively. Addition of VX into 3.5–3.7 wt % suspensions of PVAm-APy in DMSO-d6 and D2O at initial VX concentration of 0.2 vol % resulted in 100% VX degradation in less than 20 min. The unmodified PVAm and PAAm were 2 orders of magnitude less active than PVAm-APy and PAAm-APy, with VX half-lives in the range of 24 h. Furthermore, the PVAm-APy and PAAm-APy gels facilitated the dehydrochlorination reaction of sulfur mustard (HD) and its analogue 2-chloroethyl ethylsulfide (CEES). The ability of the reported aminopyridine-modified polyalkylamine materials to degrade the most persistent of CWAs, coupled with aqueous solubility, and the presence of numerous amino groups that provide convenient "handles" for covalent attachment on polymeric and inorganic supports yields promise for applications such as protective fabric and textile treatment and components of decontaminating materials.

Related Stories

In today's world, in which the threat of terrorism looms, there is an urgent need for fast, reliable tools to detect the release of deadly chemical warfare agents (CWAs). In the journal ACS Macro Letters, scientists are reporting ...

Northwestern University scientists have developed a robust new material, inspired by biological catalysts, that is extraordinarily effective at destroying toxic nerve agents that are a threat around the globe. First used ...

There was chaos on the streets of Halajba in March 1988. In this corner of Iraq, at the time Iraqi Kurdistan, people had suddenly started experiencing cold-like symptoms – tight chest and nasal congestion. Within a few ...

With fears growing over chemical and biological weapons falling into the wrong hands, scientists are developing microrockets to fight back against these dangerous agents, should the need arise. In the journal ACS Nano, they ...

America's war on terror includes fighting the dark side of deadly chemical agents, and Texas A&M University chemist Dr. Frank Raushel is helping with the fight by developing an enzyme that might neutralize one such chemical ...

Recommended for you

The storage of photogenerated electric energy and its release on demand are still among the main obstacles in artificial photosynthesis. One of the most promising, recently identified photocatalytic new materials is inexpensive ...

(Phys.org)—A team of researchers with UT Southwestern Medical Center and the University of Chicago has developed a new imaging technique that may give scientists a relatively simple means to unravel which parts of proteins ...

In the atmosphere, feldspar particles act as ice nuclei that make ice crystals grow in clouds and enable precipitation. The discovery was made by researchers of Karlsruhe Institute of Technology (KIT) and University College ...

(Phys.org)—Researchers from Ben-Gurion University of the Negev in Israel and École Polytechnique Fédérale de Lausanne in Switzerland have developed porous 200 nm supraspheres from gold nanoparticles whose surface is ...

In an algae-eat-algae world, it's the single-celled photosynthetic organisms at the top (layer of the ocean) that absorb the most sunlight. Underneath, in the sublayers, are cryptophyte algae that must compete for photons ...

0 comments

Please sign in to add a comment.
Registration is free, and takes less than a minute.
Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.